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Crotalus ruber

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA REPTILIA SQUAMATA VIPERIDAE

Scientific Name: Crotalus ruber
Species Authority: Cope, 1892
Common Name/s:
English Red Diamond Rattlesnake
Synonym/s:
Crotalus exsul Garman, 1884
Taxonomic Notes: Murphy et al. (1995) examined variation in mtDNA, allozymes, and morphology of red diamond rattlesnakes and concluded that Crotalus ruber and C. exsul should be considered a single species (C. exsul) with three subspecies (C. e. exsul, C. e. ruber, and C. e. lorenzoensis. Smith et al. (1998) applied to the ICZN to conserve the name Crotalus ruber for the red diamond rattlesnake by giving the name Crotalus ruber precedence over the name C. exsul. ICZN (2000) gave Crotalus ruber precedence over C. exsul whenever the two names are considered to be synonyms.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Assessor/s: Hammerson, G.A., Frost, D.R. & Hollingsworth, B.
Reviewer/s: Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)
Justification:
Listed as Least Concern in view of its wide distribution, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.

Geographic Range [top]

Range Description: The species' range extends from southwestern California in the United States (from near Pioneertown and Morongo Valley of San Bernardino County and southeastern Los Angeles County) south through Baja California (Mexico), including several islands in the Gulf of California (e.g., Angel de la Guarda, Pond, San Marcos, Danzante, Monserrate, and San Jose islands) and Isla de Santa Margarita and Isla Cedros along the Pacific coast of Baja California to Los Cobos (Murphy et al. 1995, Grismer 2002, Campbell and Lamar 2004). This species does not occur in the desert east of the Sierra de Juarez in northeastern Baja California (Campbell and Lamar 2004). Its elevational range extends from near sea level to about 1,500 m asl but usually below 1,200 m asl (Campbell and Lamar 2004).
Countries:
Native:
Mexico; United States
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: This species is represented by a large number of occurrences (subpopulations). In California, Jennings and Hayes (1994) mapped roughly 80 extant locations and about 45 locations from which the species was believed to be extirpated. Campbell and Lamar (2004) mapped about 27 collection sites in Baja California. The adult population size is unknown but presumably exceeds 10,000. Jennings and Hayes (1994) estimated that about 20% of the suitable habitat in California has been lost. Declines have been much less severe in Baja California, though it has disappeared from urban areas. Currently, its extent of occurrence is stable whereas its area of occupancy, number of subpopulations, and population size are probably slowly declining; overall, the rate of decline is probably less than 10% over 10 years or three generations.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: Habitats are varied and include rocky areas of tropical deciduous forest, ocean shores, desert scrub, thorn scrub, open chaparral, mesquite-cactus, and pine-oak woodland, sometimes also dunes, grassland, and cultivated areas between rock outcrops (Grismer 2002, Stebbins 2003, Campbell and Lamar 2004). In southern California, this snake is most common in the western foothills of the Coast Ranges and in dry rocky inland valleys (Ernst 1992, Ernst and Ernst 2003, based on Klauber's studies in San Diego County); it often inhabits areas of granite rock outcroppings, especially in winter (Armstrong and Murphy 1979). In southern Baja California, it is most common in heavy brush where rocks and rocky outcrops are prevalent, but it also occurs in desert and open arid plains (Armstrong and Murphy 1979). This terrestrial snake commonly climbs into low vegetation. Refuges include rock crevices, animal burrows, brush piles, surface debris, or similar sites.
Systems: Terrestrial

Threats [top]

Major Threat(s): It is threatened by habitat loss caused by residential and agricultural development in inland valleys in portions of California and Baja California, where killing by humans likely has depleted populations near developed areas (Armstrong and Murphy 1979, Jennings and Hayes 1994).

Conservation Actions [top]

Conservation Actions: Several populations are in protected areas.
Citation: Hammerson, G.A., Frost, D.R. & Hollingsworth, B. 2007. Crotalus ruber. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 17 April 2014.
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